Diode-pumped ultrafast Yb:KGW laser with 56 fs pulses and multi-100 kW peak power based on SESAM and Kerr-lens mode locking

A high-power sub-60 fs mode-locked diode-pumped Yb:KGW laser based on hybrid action of an InGaAs quantum-dot saturable absorber mirror and Kerr-lens mode locking was demonstrated. The laser delivered 56 fs pulses with 1.95 W of average power corresponding to 450 kW of peak power. The width of the generated laser spectrum was 20.5 nm, which was near the gain bandwidth limit of the Yb:KGW crystal. To the best of our knowledge, these are the shortest pulses generated from the monoclinic double tungstate crystals (and Yb:KGW laser crystal in particular) and the most powerful in the sub-60 fs regime. At the same time, they are also the shortest pulses produced to date with the help of a quantum-dot-based saturable absorber. High-power operation with a pulse duration of 90 fs and 2.85 W of average output power was also demonstrated

A Compact Multiphoton 3D Imaging System for Recording Fast Neuronal Activity

We constructed a simple and compact imaging system designed specifically for the recording of fast neuronal activity in a 3D volume. The system uses an Yb:KYW femtosecond laser we designed for use with acousto-optic deflection. An integrated two-axis acousto-optic deflector, driven by digitally synthesized signals, can target locations in three dimensions. Data acquisition and the control of scanning are performed by a LeCroy digital oscilloscope. The total cost of construction was one order of magnitude lower than that of a typical Ti:sapphire system. The entire imaging apparatus, including the laser, fits comfortably onto a small rig for electrophysiology. Despite the low cost and simplicity, the convergence of several new technologies allowed us to achieve the following capabilities: i) full-frame acquisition at video rates suitable for patch clamping; ii) random access in under ten microseconds with dwelling ability in the nominal focal plane; iii) three-dimensional random access with the ability to perform fast volume sweeps at kilohertz rates; and iv) fluorescence lifetime imaging. We demonstrate the ability to record action potentials with high temporal resolution using intracellularly loaded potentiometric dye di-2-ANEPEQ. Our design proffers easy integration with electrophysiology and promises a more widespread adoption of functional two-photon imaging as a tool for the study of neuronal activity. The software and firmware we developed is available for download at http://neurospy.org/ under an open source license

Femtosecond Cr⁴⁺:YAG laser with a 4GHz pulse repetition rate

The construction of a compact, high-repetition-rate femtosecond Cr4+:YAG laser is reported. Transform-limited pulses as short as 80 fs were generated at pulse repetition frequencies up to 4 GHz. The femtosecond pulses were tunable from centre wavelengths of 1505 to 1550 nm.</p

Femtosecond Cr⁴⁺:YAG laser with a 4GHz pulse repetition rate

The construction of a compact, high-repetition-rate femtosecond Cr4+:YAG laser is reported. Transform-limited pulses as short as 80 fs were generated at pulse repetition frequencies up to 4 GHz. The femtosecond pulses were tunable from centre wavelengths of 1505 to 1550 nm.</p

Compact self-starting femtoseocnd Cr⁴⁺:YAG laser diode pumped by a Yb-fiber laser

We report a compact self-starting passively mode-locked femtosecond Cr:YAG laser which incorporates a saturable Bragg reflector and uses a diode-pumped Yb-fiber laser as the pump source. Transform-limited 120-fs pulses are generated at an average power of 95 mW with a 22 nm spectral bandwidth centered at 1528 nm. (C) 2003 Elsevier Science B.V. All rights reserved.</p

Compact self-starting femtoseocnd Cr⁴⁺:YAG laser diode pumped by a Yb-fiber laser

We report a compact self-starting passively mode-locked femtosecond Cr:YAG laser which incorporates a saturable Bragg reflector and uses a diode-pumped Yb-fiber laser as the pump source. Transform-limited 120-fs pulses are generated at an average power of 95 mW with a 22 nm spectral bandwidth centered at 1528 nm. (C) 2003 Elsevier Science B.V. All rights reserved.</p